Drink everyday but low tolerance

I’m a bartender so I drink basically every single day. When I’m working I can easily have 7-8 shots of tequila, two double rums and a lager feeling fine. When I have a day off I will have 4 shots of any spirit before bed. But when I go out with friends, having just 4 lagers will make me wasted…

Maybe it’s because I typically drink spirits? But my tolerance doesn’t seem to go up despite drinking what is arguably a lot. I also get crazy hangovers most days.